The Influence Of Troxerutin To Cognitive Function Of STZ Diabetic Rats And NADPH Oxidase P22phox

Objective:With the incidence of diabetes increased, Diabeticencephalopathy are more and more concerned. The main clinicalmanifestation is the cognitive dysfunction. The pathogenesis of diabetesencephalopathy is not yet clear. The oxidative stress is one of the importantpathogenesis. NADPH oxidase(NOX) played central role. The superoxidedismutase (SOD) and malondialdehyde (MDA) are the main index of the levelin the oxidative stress test. Troxerutin was an Chinese medicine with strongantioxidant effect.In the study, we constructed the STZ diabetes rat modelwith cognitive dysfunction,comparing with antioxidant alpha lipoic acid(α-LA), this study will observe the impact of troxerutin on diabetic rat behavior,the subunit p22phox of NADPH oxidase,SOD activity, MDA content.Methods:1Diabetic rats model preparation:The diabetic rat models were induced by intraperitoneal injection ofstreptozotocin(STZ)(60mg/kg). After3days, random blood glucose monitoredby tail-vein sampling≥16．7mmol／L was our criterion for experimentaldiabetes, and appeared cognitive dysfunction after raising12weeks.2GroupHealthy male Sprague Dawley(SD) rats (weight150-170g n=70),randomly divided into:Normal control group (NC group, n=10), diabetes group (DM n=60);iabetes group randomly divided into:Diabetes control group (DC n=15); Diabetic group treated with normalsaline (DN, equal volume of citrate buffer solution intraperitoneal injectionn=15); Diabetic group treated with alpha lipoic acid group (DL,60mg/kgintraperitoneal injection of alpha lipoic acid n=15); Diabetic group treated with troxerutin (DT,60mg/kg intraperitoneal injection of troxerutin n=15).The intraperitoneal injection was taken from the thirteen week and lasted forsix weeks.3General observation: observe and record the mental state, the quantity ofeat.drink.urinary volume,the change of blood glucose and the weight.4Morris water maze test: each rat group was taken at the first, twelfth andnineteen week point. The escape latency was recorded and analyzeed thechange of the learning ability of rats.5Sample preparation and observation index:After six weeks′drug intervention,the brain organization was taken, The SOD activity and MDA content inhippocampus were separately detected by methods of xanthine oxidase andthiobarbituric acid.The expression of p22phox was detected by real-timequantitative polymerase chain reaction (Real-Time PCR) and Westernblotting.6Statistics method: the statistical analysis was SPSSl3.0. We used therepeated measurement data of variance analysis, the single factor analysis ofvariance (One Way ANOVA). To P <0.05for significantly.Results:1Generally observation, blood sugar and weightNC group rats were in good shape with pure white and glossy fur, theynormal eating and drinking, uresis and steady growth(338.21±43.47). Thediabetic rats gradually appeared gloomy sparse dull,fur and loose stools. Theappeared polyuria,polydipsia,polyphagia,and have significant weight loss(290.25±40.31) compared with NC group(P<0.05); the blood glucose(27.35±4.31) increased significantly compared with NC group(6.89±0.65),(P<0.05).2Morris water maze results (escape latency)At the first week point, there was no significant difference between DMgroup and the NC group (P>0.05);At the twelve week point,after building the model, the escape latency ofdiabetes group was significantly longer than NC group (P <0.05); At the nineteen week point(drug intervention after), the escape latency ofDL group and DT group reduced significantly comparing with DC group andDN group, but was still higher than NC group (P<0.05); There were nosignificant difference between DL Group and DT group (P>0.05); Therewere no significant difference between DC and diabetes DN group (P>0.05).3The SOD and MDA results:SOD activity: the SOD activity of DC group(61.81±3.94) and DN group(68.24±7.62) were significantly lower than the NC group(115.98±7.57),(P <0.05); The DL groupp(200.32±6.1) and DT group(191.99±11.41) weresignificantly higher than DC group, DN group (P <0.05); the SOD activity ofDT group were significantly lower than the DL group (P <0.05);There wereno significant differences between DC and DN group (P>0.05).MDA content: the MDA content of DC group(3.83±0.11) and DNgroup(3.71±0.20) were significantly higher than the NC group(2.74±0.21),(P<0.05); the MDA content of the DL group(2.02±0.23) and DT group(2.54±0.20) were significantly lower than DC group, DN group (P <0.05); theMDA content of DT group were significantly higher than the DL group (P <0.05);There were no significant differences between DC and DN group (P>0.05).4Real-Time PCR results(p22phox mRNA expression):The expression of DN group(1.48±0.28) and DC group(1.50±0.33)were obviously higher than NC group,the DL group and DT group weresignificantly lower comparing with DC group and DN group (P <0.05); Therewere no significant difference between DL group and DT group (P>0.05),andno significant difference between DC and DN group (P>0.05).5Western blot results (p22phox protein level)The protein levels of DN group(1.48±0.28) and DC group(1.50±0.33)were obviously higher than NC group(1±0,P <0.05); The protein levelof DL group(0.65±0.21) and DT group(0.74±0.26) were significantlylower comparing with DC group and DN group (P <0.05); There were nosignificant difference between DL group and DT group (P>0.05),and no significant difference between DC and DN group (P>0.05).Conclusion:1Diabetes can lead to cognitive dysfunction.2Troxerutin can improve STZ diabetic rats cognitive dysfunction, but theeffect was no obvious difference toα-LA.3The p22phox mRNA and protein levels of STZ diabetic rats Hippocampusincreased.4Troxerutin can reduce p22phox mRNA and protein expression, Increase theSOD activity, reduce the MDA content of STZ diabetic rats Hippocampus.5It was speculated that troxerutin can improve STZ diabetic rats cognitivedysfunction through reducing the oxidative stress level and improving theability of antioxidative stress.